The many breeds of dogs show that selective breeding can
be used to make great changes in their inherited physical
characteristics.
B.
Our oldest clue about the domestication of dogs is the
discovery of wolf bones buried together with human bones in
a cave that people lived in about 14,000 years ago.
C.
It is generally observed with many wild animals that they
can be tame when young but become wild again when they grow
up.
D.
The first step in domestication could have happened without
any planning at all. . . . It's easy to imagine a child bringing
home a lost cub: "Mom, may I keep it?"
